I am our orgs admin and I am trying to fix code set up in 2016 by a previous employee. I know very little about apex but I understand my SOQL query is pulling 0 records and I need to solve for that. I am recieving the following emails. Thank you in advance, Ive been working on this for days! 
"OrderTrigger: execution of AfterInsert
caused by: System.NullPointerException: Attempt to de-reference a null object
Class.OrderTriggerHandler.insertOrder: line 21, column 1
Trigger.OrderTrigger: line 4, column 1"

My trigger is very short, i have bolded line 4 per the email error:

trigger OrderTrigger on Order (after insert) {

    if(Trigger.isInsert){
       OrderTriggerHandler.insertOrder(Trigger.new);  
     }

}

My handler is as follows, i have bolded line 21 per error email:
public with sharing class OrderTriggerHandler{

    public Static void insertOrder(List<Order> objOrder)
    {
        
         Set<Id> objAcc = new Set<Id>();
         for(Order objOr : objOrder){
             objAcc.add(objOr.AccountId);
         }
         
         
         List<Contact> objCon = [select id,name,Email,AccountId,Account.Parent.ParentId, Account.Parent.Parent.Name from Contact where AccountId IN : objAcc];
         String partnerName;
         Id wideEmailAddressId;
         if(objCon.size() > 0){
             List<String> objMail = new List<String>();
             Set<String> objSetAcc = new Set<String>();
             for(Contact objContact : objCon){
                 objMail.add(objContact.Email);
                 partnerName = objContact.Account.Parent.Parent.Name;
                 String accId = String.valueOf(objContact.Account.Parent.ParentId).substring(0, 15);
                 objSetAcc.add('New Order Notification'+accId);
             }
             
        for(OrgWideEmailAddress owa : [select id, Address, DisplayName from OrgWideEmailAddress where DisplayName='EvoLaw, LLC']) {
             if(owa.Address.contains('CSR')) wideEmailAddressId = owa.id; 
        } 
        System.debug('&&&&&&&objSetAcc&&&&&& '+objSetAcc);
        
        
       List<EmailTemplate> templateId = [Select id,Subject, HtmlValue, Body from EmailTemplate where name IN : objSetAcc];
       System.debug('&&&&&&&templateId&&&&&& '+templateId);
       if(templateId.size() > 0){ 
       
            System.debug('&&&&&&&templateId &&&&& '+templateId[0]); 
           String [] emailsAsArray = new String [objMail.size()];
            Integer i = 0;
            for (String singleCCEmail: objMail) {
                emailsAsArray[i++] = singleCCEmail;
            }  
             
           
           String subject =templateId[0].Subject ;
           String htmlBody = templateId[0].HtmlValue ;
           String plainBody = templateId[0].Body;
         
          
          // Messaging.sendEmail(new Messaging.Singleemailmessage[] {mail});
     @TestVisible Messaging.SingleEmailMessage message = new Messaging.SingleEmailMessage();
            message.toAddresses = emailsAsArray;
            message.optOutPolicy = 'FILTER';
            message.subject = 'Opt Out Test Message';
            //message.plainTextBody = 'This is the message body.';
             if(templateId[0].id != null)
             message.setTemplateId(templateId[0].id);
             if(wideEmailAddressId!=Null)
             message.setOrgWideEmailAddressID(wideEmailAddressId);
             message.setSubject(subject);
             message.setHtmlBody(htmlBody);
             message.setPlainTextBody(plainBody);
            // message.setTreatBodiesAsTemplate(true);
            Messaging.SingleEmailMessage[] messages =  new List<Messaging.SingleEmailMessage> {message};
            System.debug('___________msg____' +messages );
            Messaging.SendEmailResult[] results = Messaging.sendEmail(messages);
            if (results[0].success) {
                System.debug('The email was sent successfully.');
            } else {
                System.debug('The email failed to send: '+ results[0].errors[0].message);
            } 
             
           }
         }
    }

}